About Lesson
Function – Implementation Rule
1. Declaration or Prototype of function (Always above the main() )
Syntax –
ReturnType FunctionName(DT, DT,…);
example:
void msg(); // does not return and does not accept
void sum(int,int); // sum is a function and it does not return but accept 2 int
void table(int);
int fact(int);
float getpi();
float result(int,int,int,int,int);
void mean – function does not return
empty parenthesis – function does not accept
Return Accept
No No
No Yes
Yes Yes
Yes No
2. Definition (Below the main() )
Syntax –
ReturnType FunctionName(DT var, DT var,…)
{
……
……
return value; //optional
}
3. Calling (Inside the main() )
Sytax –
funname(val,val,…);
C
#include<stdio.h>
void msg(); // does not accept and does not return
void sum();
int main() // a name which is given to set of instructions
{
msg(); // calling
sum(); // calling
msg();
return 0;
}
void msg() // definition
{
printf("\nHello User");
printf("\nWelcome to function");
}
void sum()
{
int n1,n2,t;
printf("\nenter 2 nos");
scanf("%d%d",&n1,&n2);
t=n1+n2;
printf("\nSum=%d",t);
}